1. Field of Invention
The present invention relates to a liquid supply method for supplying a liquid, such as ink, from a liquid storage unit for storing the liquid to a liquid ejection unit.
2. Description of Related Art
Until now, an ink jet-type printer (hereinafter referred to as “printer”) disclosed in JP-A-2000-211152 has been proposed as a liquid ejecting apparatus capable of supplying a liquid from a liquid storage unit for storing the liquid to a liquid ejection unit. The printer disclosed in JP-A-2000-211152 includes a recording head serving as a liquid ejecting unit for ejecting ink as the liquid onto a target such as recording paper, and a sub-tank for temporarily accommodating the ink to be supplied to the inside of the recording head. The inside of the sub-tank is supplied with the ink from an ink cartridge, which serves as a liquid storage unit, via an ink supply tube.
Recently, as the ink to be ejected onto the target, UV (Ultra Violet) ink which is cured by irradiation of ultraviolet rays has been used. A portion of the ink component may be easily settled in the ink cartridge which stores the high viscosity ink, such as UV ink. For this reason, a component ratio of the ink supplied to the recording head via the sub-tank from the ink cartridge may vary slightly whenever a process of supplying the ink from the ink cartridge side is performed. Accordingly, a variation occurs in the component ratio of the ink ejected from the recording head, and, as a result, it is difficult to constantly maintain the quality of a product (i.e., a target of printing completion) made by ejecting the ink onto the target.
In addition, if the ink is accommodated in the sub-tank for a long time, a portion of the ink component may be settled in the sub-tank. In a case where the ink is supplied to the recording head side from the sub-tank in this state, a variation may occur in the component ratio of the ink which is ejected from the recording head.